It may not have been mentioned here, but Intel has
released the programmer interface specs to their RNG, at
http://developer.intel.com/design/chipsets/manuals/298029.pdf.
Nothing prevents the device from being used in Linux /dev/random now.
As for the concerns about back doors, the best reference on
the design of the RNG remains cryptography.com's analysis at
http://www.cryptography.com/intelRNG.pdf. Paul Kocher and his team
concluded that the chip was well designed and that the random numbers were
of good quality. (Note, BTW that the RNG is extremely small, crammed
into the margins of the device. An RNG which produced undetectably
backdoored random date would probably be an order of magnitude larger.)
Even if Intel wanted to put in a back door, it would be very difficult
to exploit it successfully. There is no way for the chip to predict how
any given random bit will be used: it may go into a session key directly,
it may be hashed through some kind of mixing function along with other
sources of randomness, it may seed a PRNG which is then used to find
RSA primes. There are a multitude of different possibilities and it
would be hard in general to design an effective backdoor without knowing
how the output will be used.
And as pointed out before, this level of paranoia is ultimately self
defeating, as Intel could just as easily put back doors into its CPU.
Unless or until you are willing to use a self-designed and self-fabbed
CPU, you are fundamentally at the mercy of the hardware manufacturer.
